Cigarette smoking remains the single largest preventable cause of premature death and disability in the United States, and effective antismoking campaigns require an empirical understanding of the natural history of smoking and its determinants. The proposed research extends our cohort-sequential study of smoking and its intergenerational transmission and integrates this study with an experimental, translational application to family-based smoking prevention and midlife cessation. Cohorts of 6th-12th graders (N=8,521) were followed annually between 1980-1983 to prospectively predict adolescent smoking transitions with social psychological models. Four additional follow-ups were conducted in 1987-1988; 1993-1994; 1999-2000, and 2005-2006 (for a total of eight measurement waves with more than 70% retention of the total sample at each wave). Web-based studies of implicit attitudes toward smoking and their role in smoking transitions and the intergenerational transmission of smoking were initiated in the last project period. The proposed studies combine a 9th measurement of our total sample using a mailed survey with short-term longitudinal, studies of targeted subgroups using web-based methods. We embed smoking in a developmental context by relating smoking trajectories to the unique hallmarks of midlife development, and by relating midlife conditions to parents' socialization of smoking in the next generation. We then employ these data in a translational application to family-based smoking prevention and midlife cessation. Using web-based, experimental, short-term longitudinal studies of targeted subgroups, we will test the effects of approach-avoidance practice and an anti-smoking PSA on an unobtrusive measure of engagement with intervention information. We will test whether the effects of our interventions are mediated by changes in implicit attitudes, and we will identify the component automatic and controlled processes of implicit attitudes that are responsible for these effects (and that are predictive of later smoking outcomes). The results will be important for improving engagement in family-based smoking prevention programs, tailoring smoking cessation messages aimed at midlife adults, and understanding the intergenerational transmission of smoking.